Problem: Himari gave birth to twins and named them Adrian and Chang. When they were first born, Adrian massed $2.87$ kilograms and was $54.5$ centimeters tall, and Chang massed $4.54$ kilograms and was $51$ centimeters tall. How much did the babies mass in total?
Answer: Adrian's mass $+$ Chang's mass $=$ total mass. $\begin{matrix} &{1}&&\\ &{2}.&8&7\\ +&{4}.&5&4\\ \hline &{7}.&4&1\\ \end{matrix}$ ${1}+{2}+{4}={7}$ The total mass of the babies is $7.41$ kilograms.